Concept
of
Symmetry
inClosure
Spaces
as a Toolfor
Naturalization of Information
Marcin J. Schroeder
Akita Intemational
University,
Akita, Japanmjs@aiu.ac.jp
1. Introduction
Tonaturalizeinformation,i.e.tomake theconceptof informationasubjectof thestudyofreality
independent from subjective judgment requires methodology of its study consistent with that of
natural sciences.Section 2 of thispaperpresentshistoricalargumentationfor the fundamental role of thestudyofsymmetriesinnaturalsciences and in the consequenceof the claim that naturalization of
informationrequiresamethodologyof the studyofits symmetries. Section3 includes mathematical
preliminariesnecessaryfor thestudyofsymmetriesinanarbitraryclosure space carriedoutin Section 4. Section5demonstrates theconnection of theconcept ofinformation and closurespaces. Thissets foundations forfurtherstudies ofsymmetriesof information.
2.
Symmetry
andScientificMethodology
Typicalaccountof theoriginsof the moderntheoryofsymmetrystartswithErlangen Programof
Felix Kleinpublishedin 1872. [1] Thispublicationwasofimmense influence. Kleinproposeda new
paradigm of mathematical study focusing not on its objects, but on their transformations. His
mathematicaltheoryofgeometricsymmetrywasunderstoodas aninvestigationof the invariance with
respect to transformations of the geometric space (two‐dimensional plane or higher dimensional
space).Klein used thisverygeneralconceptofgeometricsymmetryfor the purposeofaclassification
of different types of geometries (Euclidean and non‐Euclidean). The fundamental conceptual
framework of KleinsProgram(asitbecame functionasaparadigm)wasbasedonthe schemeof(1)
space as a collection ofpoints \rightarrow (2) algebraic structure (group) of its transformations \rightarrow (3)
invariants ofthetransformations,i.e. configurationsofpointswhich donotchangeas awhole,while
theirpoints are permuted by transformations. Selections ofalgebraic substructures (subgroups) of
transformations correspond to different types and levels of invariant configurations allowing to differentiate andtocomparestructuralpropertiesassociated withsymmetry.The classicalexampleof the mirror symmetry (symmetry with respectto the surface of the mirror) can be identified with
invariance withrespecttomirror reflection.
Kleins workwasutilizinga newtheoryofgroups which in the worksofArthurCayley [2],Camille
Jordan [3] and others foundits identity as apartofalgebra. KleinsErlangen Program to classify
geometries has been extended to many other disciplines of mathematics becoming one ofmost
commonparadigmsofthemathematical research.Also,in the consequence ofoneofmostimportant
contributionstomathematical physics of all timespublishedin 1918Uy EmmyNoether [4] stating that every differentiable symmetry of the action of a physical system has a corresponding
conservationlaw,the invariance withrespecttotransformations,i.e.symmehywithrespecttothese transformations, became the central subjectofphysics. The fact that the conservation laws for the
physical magnitudes suchas energy,momentum, angularmomentumareassociatedUythe theorem
with transformations describing changes of reference frames, i.e. observers makes the study of symmetryacentral tool for scientificmethodology. Physics (andscience ingeneral)islookingforan
objective descriptionofreality,i.e.descriptionthat is invariantorcovariant withchangesof observers. Noethers theoremtellsusthat suchdescriptioncanbe carriedoutwith conservedmagnitudes.
The year 1872 whenErlangen Program waspublishedcanbe considered thestarting pointof the studyofsymmetriesintermsof the grouptheory,butnotof thescientificstudyofsymmetries. The
importanceofsymmetries,stillunderstood intermsofthe invariance but ofthe mirror reflectionsonly
wasrecognized longbeforeErlangen Programinthecontextofbiochemistry.LouisPasteurpublished
in 1848 one ofhis most important papers explainingisomerism oftartrates, more specificallyof
tartaric acidbythemolecularchirality.[5] Heshowedthat the differences betweenoptical properties of the solutions of this organic compound between samples synthesized in living organisms and samples synthesized artificiallyresult from the fact that inartificially synthesizedmoleculesalthough constructed from the same atoms as those in natural synthesis, have twogeometric configurations
whicharesymmetricwithrespecttothemirrorreflection,butnotexchangeable Uy spatialtranslations
orrotations (thesame way as left and right palms of humanhands), while in the nature onlyleft‐ handedconfigurationsoccur. Laterit tumedoutthatalmostexclusively naturally synthesizedamino acids(andthereforeproteins)areleft‐handed,andsugarsarerighthanded.Artificialsynthesis,if not constrained by special procedures leads to equal production of the left and right handedness. There isnocommonly accepted explanationofthismysterious phenomenoneventoday.
Thestructural characteristic whichgivesthe distinctionofleft andrighthandednesswasgivenname
ofchirality. Thus, our hands are chiral, while majority ofsimple organisms are symmetric with
respectto rotations, and therefore achiral). Chirality of molecules became one ofmost important
subjectsofthe 19^{\mathrm{t}\mathrm{h}}Century biochemistry leadingtothediscoveryofthe role oftheatomsof carbonin
formation of chiral molecules formulated into Le Bel —vant Hoff Rule published by these two researchersindependentlyin1874.
Thestudyofsymmetryinbiology,inparticularofchiralityincomplex organisms couldnot have
been explained in the 19^{\mathrm{t}\mathrm{h}} Century, but researchers published some phenomenological laws of
evolutionandphenotypic developmentoforganisms, suchasBatesons Rule. Much later Batesons
sonprovided explanationof this rulein termsofinformation science. [6, 7]Similarinterpretationcan
be givento Curies Dissymmetry Principle.Pierre Curie made so manyimportant contributionsto
physicsandchemistrythatthis fundamentalprincipleofgreatimportance israrely invoked.Its little bit outdatedoriginalformulationusingthetermdissymmetryinsteadofnow commonasymmetry
was:Aphysicaleffectcanmothaveadissymmetryabsent from itsefficientcause.
The real importance of these early developments could be fully appreciated ahalfcentury later
whenit becamefullyclear thankstoadvances inphysics(elementaryparticletheory)thatthestudyof the conditions formaintainingsymmetryisno moreimportantthan thestudyofbreakingsymmetry.
By the mid‐20th Century the study ofsymmetry became a fundamental tool for mathematics,
physics,chemistryandfor several branches ofbiology.Thiscanexplainsuddenexplosionof interest
insymmetryamongphilosophers.The swingof thependulum ofdominating philosophical interests
between seeking an objective methodology for philosophical inquiry inspired Uy scientific
methodologyand introspective andtherefore subjective phenomenal experiencereached the side of the former.
Thebeginningsof structuralism canbetracedtotheworks of Ferdinand deSaussureonlinguistics
(more specificallyhis lectures 1907‐1911 posthumously published byhis disciplesin 1916[8]).The emphasis onthe structural characteristics oflanguage andon their synchronous analysis prompted
increased interest in the meaningof the conceptofstructure. Itwas anatural consequencethat the
toolsusedinscience for the structuralanalysisintermsofsymmetryfound theirwaytopsychology, anthropology and philosophy. The most clearprogrammatic work on structuralism by Jean Piaget publishedoriginallyin 1968isreferringexplicitlytotheconceptof thegroupoftransformations. [9]
Piagetbased histheoryof childdevelopmentonthesocalled Kleins(sic!)fourgroup.The works ofothers, for instance of Claude Levi‐Strauss, also employed directly the methods developed in consequenceofErlangen Program. [10]
Theswingof thependulumreversed its directionandstructuralism lost hisdominating positionto
itscritique,but itsimportancecanbeseenin thenameof this reversedswingaspost‐structuralism.
Some ofthis criticism is naive. For instance, structuralism was criticized as dry or too much
formal. The definite record ofdryness is held and probably always will Ue held by Aristotle,
togetherwith the titleof themostinfluentialphilosopherof all times. Morejustified objectionof the lack ofexplanationoftheoriginofthestructuresconsideredinthe studies ofPiaget,Levi‐Strauss and
others and themissing evolutionaryordynamic theoryofstructurescanbe blamedontheseauthors, but it is more a matter of misunderstanding of the mathematical tools. Physics, chemistry have
powerful dynamictheories oftheir structures,sothere isnogoodreasontobelieve that suchdynamic approachisimpossibleinphilosophy.
Symmetry canbe easilyidentified inthe studies ofvisual artsand music. Actually,the structural study of music initiated by Pythagoreans found its wayto mediaeval philosophy viaNeoplatonic
authorsand thentotheworks ofthe foundersofmodernscience suchasJohannesKepler.The music
ofHeavens,understoodliterallyasmusicproduced bythe motion oftheplanetswasamathematical
model of the universe. In modern mathematics we can easily understand the reasons for the
effectiveness of such models. Modem spectral analysis in physics is not very far from the
decompositionof functionsdescribing physical phenomenaintohamoniccomponents,thesameway asrecordingof music indigitalformat is done.
Theuniversal characterof thestudyofsymmetryinthespiritof KleinsErlangen Programbecame
commonly recognized inthe second half of the 20^{\mathrm{t}\mathrm{h}}Century. The immensepopularityof the book
Symmetry byHermannWeyl greatlycontributedtothisrecognition.[11]Atthis time grouptheory
in thecontext ofsymmetriesbecame aneveryday tool for allphysicists andassumed apermanent
placeinuniversitycurricula forstudies inphysics, chemistryandbiology. [12]Thestatement froman
article published in Science in 1972 by a future Nobel Prize laureate in Physics Philip Warren
AndersonItisonlyslightlyoverstatingthecasetosaythatphysicsisthestudyofsymmetrywas alreadyatthattimecommonly acceptedtruth.[13]
Study ofsymmetry became afundamental methodological tool. Andersons article wasnot only closing the century of the development of this tool, but it also included another very important
message.Andersonemphasizedthe role ofbreaking symmetry. Hedemonstrated that thephysical
realityhas ahierarchic structure ofincreasingcomplexity and that thetransition fromone level of
complexitytothe nextis associated withbreakingsymmetryunderstoodasatransformation of the
group ofsymmetryto another oflower level.Thus, notonlythestudyofsymmetry,but also of the
ways of itschangesisimportant.For this purpose theconceptofsymmetryhastohavevery clear and
preciseformulation.Unfortunatelytherearemanycommonmisunderstandings.
Themosttypical misunderstandingisaconsequenceofmisinterpretationof KleinsProgram.The
missingpartis the role ofprojectivegeometry.Klein didnotconsiderarbitrarytransformations ofthe plane (orsetofpointsonwhichgeometryis defined),butonlythose whicharepreservingthismost fundamental geometric structure. This very important, but very frequently ignored aspect of the
ProgramwasclearlydescribedinWeylsbookpopularizingsymmetryinthegeneralaudience: What has all thistodo withsymmetry?Itprovidestheadequatemathematicallanguagetodefine it. Givena
spatial configurations^{\infty},thoseautomorphismsofspace which leave s\leftarrowunchangedformagroup $\Gamma$,and
this group describes exactly the symmetrypossessed by s^{\infty}. Space itself has the full symmetry
correspondingtothegroup of all automorphisms,of all similarities. Thesymmetryofany figurein space is describedbyasubgroupofthatgroup [11]
The methodological aspects of the study ofsymmetry in physics suggest that the concept of
informationcanbenaturalized,i.e.canbecomeapartof the scientificdescriptionofreality,ifwecan develop methods of study of information in terms of symmetry. But to develop a theory of
information symmetry we have to generalize the concept ofsymmetry from the closure space
3.
Algebraic
PreliminariesThefollowingnotation andterminologicalconventions will beusedthroughoutthetext:
Fin(S) is a set of all finite subsets of the setS. Greekletters such as $\phi$, $\varphi$, $\Theta$, etc. will indicate
functionsonthe elements ofagivensetand withthe values belongingto aset. Small Latin letters suchas\mathrm{f},\mathrm{g}, \mathrm{h},etc. will indicatefunctions definedonthe subsets ofagivensetand with the values
whicharesubsets ofthisset.The doubleuseofthesymbol
$\varphi$^{-1}(\mathrm{A})
,asthesetof valuesfortheinversefunction of $\varphi$, and as aninverseimageofasetA withrespecttofunction $\varphi$ which does nothave
inverse,shouldnotcauseproblems.Thecompositionoffunctions will be writtenasajuxtapositionof
theirsymbols,unlessthe fact oftheuseofacompositionof functions is contrasted withconstructing
functionimages.Thesymbol\congindicatesabijective correspondenceorisomorphism.Throughoutthe
paper,partiallyorderedsetsareoftencalledposets.
Preliminariesinclude severalpropositionswithoutproofs, somebelongtothefolkloreof the subjectandarewellknown, somehaveproofs straightforward. Anintroductiontothesubjectcanbe
found in Birkhoffs LatticeTheory. [14]
DEFINITION 3.1 Let fbe afunction from thepowerset ofaset Sto itselfwhichsatisfiesthe followingtwoconditions:
(l) VA\subseteq S:A\subseteq f(A),
(2) VA,B\underline{c}S.\cdot A\subseteq B\Rightarrow f(A)\subseteq f(B), (3)VA\subseteq S.\cdot ff(A)=f(f(A))=f(A).
Thenfiscalledanoperator(ortransitiveclosureoperator)onS. Thesetofalloperatorsontheset
S isindicatedby I(S).Asetequippedwithaclosureoperatorwillbe calledaclosure space<S,f>.
The third conditionscanbereplaced byacondition: whichis easiertouseinproofs, but whichin
combination with othertWogivesexactlythesameconcept:
(3^{*})VA_{2}B\subseteq S.\cdot A\subseteq f(B)\text{ニ}>f(A)\subseteq f(B).
The strongerform ofthis conditionVA,B\subseteq S.\cdot A\subseteq f(B) iff f(A)\subseteq f(B)canbe used insteadofallthree
conditions to define a transitive operator, but this fact does not have a significant practical
importance.
DEFINITION 3.2 Letfbeaclosureoperatoron asetS. The subsets AofS satisfyingthecondition
f(A)=A, calledf‐closedsetsform a Moorefamily f‐Cl, i.e. it is closed with respectto arbitrary
intersections andincludes thesetS(whichcanbe consideredthe intersectionoftheemptysubfamily of subsets). EveryMoorefamily M defines a transitive operatorf(A)=\displaystyle \cap\oint M\in M:A\subseteq MJ. Set
theoreticalinclusiondefinesapartialorderon f‐Clwithrespecttowhich it isacompletelattice. To
thisstructurewewillreferasthecompletelatticeL_{f} off‐closed (orjust closed)subsets.
Letfand g beoperatorson asetS. Therelationdefined byf\underline{<}g if VA\subseteq S:f(A)\subseteq g(A)isapartial
orderon I(S), withrespect towhich it is acomplete lattice. Thispartial ordercorresponds tothe
inverseoftheinclusionofthe Moorefamilies ofclosedsubsets
DEFINITION 3.3Letfbeaclosureoperatoron asetS,gaclosureoperatoronsetT,and $\varphi$ bea
function from Sto T. Thefunction $\varphi$ is ffg)‐continuous if VA\subseteq S.\cdot $\varphi$ f(A)\underline{c}g $\varphi$(A). We willwrite
continuous,ifno confusionislikely.
PROPOSITION 3.1 Continuity ofthefunction $\varphi$ as definedabove is equivalent to each ofthe
followingstatements:
(2)
VB\subseteq T.\cdot f$\varphi$^{1}(B)-\subseteq$\varphi$^{\mathrm{J}}g(B)-,
(3)VB\underline{c}T:ff$\varphi$^{1}(B)\subseteq g(B)-.
(4)VB\in g-C.\cdot $\varphi$(B)\in f-C-.
DEFINITION 3.4 Letfbeaclosureoperatoron asetS,gaclosureoperatoronsetT,and $\varphi$ bea
functionfrom StoT. Thefunction $\varphi$ is (fg)‐isomorphism ifit isbijectiveand VA\underline{c}S:ff(A)=g $\varphi$(A).
Wewillwriteisomorphism, ifno confusionislikely. IfS=T, wewill call $\varphi$an(fg)‐outomorphism, or
smply automorphism.
PROPOSITION 3.2 Theconditionsforafunction $\varphi$tobe an isomorphism, asdefinedabove, are
equivalenttoeitheronebelow:
(1) $\varphi$ hasaninverse
$\varphi$^{l}-
,and both arecontinuous,(2)Thereexistsafunction $\psi$from TtoSsuch that $\varphi \psi$=id_{T} and $\psi \varphi$=id_{S} and both $\varphi$ and $\psi$ are
continuous.
PROPOSITION 3.3Letfbeaclosureoperatoron aset S,gaclosureoperatoronsetT, and $\varphi$ bea
functionfrom StoT. Then, every(fg)‐isomorphism $\varphi$generatesalattice isomorphism$\varphi$^{*}between the
completelatticesofclosed subsetsL_{f}andL_{g} defmed byVA\in L_{f}\cdot$\varphi$^{*}(A)= $\varphi$(A)\in L_{g}.Also, ifafunction
$\varphi$:S\rightarrow Tisbijectiveandisgeneratingalatticeisomorphism $\varphi$^{*}betweenlatHces L andLg., then $\varphi$ is an rgJ‐isomorphism.
COROLLARY 3.4Everyf‐authomorphism $\varphi$ of<SJ>generatesauniquelatticeautomorphism of
L However, more than onef‐authomorphism $\varphi$ of<Sf>can correspond to the same lattice
automorphismofL_{f}
PROPOSITION 3.4 The set ofallf‐automorphisms of<Sf> formsagroupAut<SJ> under the
function composition. Thisgroup isisomorphictoAut(Ldoflatticeautomorphisms ofL
Wewillrefertotheconceptofan(antisotone)Galois connectionbetweentwoposets.
DEFINITION 3.5Let<P,\underline{<}>and<Q,\underline{<}>be posets and $\varphi$ and $\psi$ be anti‐isotone(order inverting) functions $\varphi$:P\rightarrow Qand $\psi$ Q\rightarrow P.Then thefunctions defineaGalois connectionbetween the posets
if. \mathrm{t}\mathrm{l}\mathrm{X} $\epsilon$ P:x\underline{<} $\psi \varphi$(x)andVy $\epsilon$ Q.\cdot y\underline{<} $\varphi \psi$(y).
Galois connectioncanbedefinedinanequivalentwayas apairoffunctions $\varphi$:P\rightarrow Qand $\psi$ Q\rightarrow P
suchthat Vx\in PVy\in Q.\cdot y\underline{<} $\varphi$(x)iff x $\Xi \psi$(y).
PROPOSITION 3.5Ifapairoffunctions $\varphi$:P\rightarrow Qand $\psi$\cdot Q\rightarrow PdefinesaGalois connection, then
thefunctions $\psi \varphi$.\cdot P\rightarrow Pand $\varphi \psi$\cdot Q\rightarrow Qareclosure operators, i.e. they satisfythe conditions1)-3) of
Definition3.1generalizedfromtheinclusion \underline{\subseteq}to thepartialorder‐<.Moreover,thefunctions $\varphi$.\cdot P\rightarrow
Qand $\psi$ Q\rightarrow Pdefineorderanti‐isomorphism (orderreversingfunctionspreservingallinfimaand
suprema) betweenthecompletelatticesofclosedelements intheposetsPandQ.
PROPOSITION 3.6 Given an anti‐isotone function $\varphi$:P\rightarrow Q. If thefunction $\varphi$.\cdot P\rightarrow Q defines
togetherwith $\psi$ Q\rightarrow PaGalois connection,then thefunction $\psi$ is unique. However, thereareanti‐
isotonefunctionswhich donotformaGaloisconnectionwithanyfunction.
PEOPOSITION 3.7Ifposets<P,\underline{<}>and<Q,\underline{<}>arecompletelattices,thenforevery anti‐isotone function $\varphi$:P\rightarrow Q, thereexists(byProp. 3.6unique) junction $\psi$ Q\rightarrow P, such thatthey formaGalois
connection.Thefunction $\psi$ Q\rightarrow Pisdefined by: $\Phi$\in Q.\cdot $\psi$(y)=\vee\{x\in P:y\underline{<} $\varphi$(x)J, whereisthe lowest
upperboundoftheset, whichmustexist inacompletelattice.
4.
Concept
ofSymmetry
inGeneral ClosureSpaces
Intheabstract formulation ofgeometryontheplaneinthetermsofclosurespaces theonlyclosed subsets are entire plane, empty subset, points and straight lines. Geometric configurations are
collectionsofpoints orlines. However, theconcepts ofclosure spaces do notgiveusany tools for
analysisofsuchconfigurations beyondthe intersections oflinesproducing pointsandpairsofpoints
defininglines. Ourgoalisto providethe tools for theanalysis of suchconfigurations notonlyfor
abstractgeometries,but forarbitraryclosurespaces.Theapproach presentedbelowwasinformedby
theanalogywithgeometric symmetriesinthe choice ofgrouptheoryasafoundation. Sincewewill use only rudimentary facts about group actions on a set, there will be no need for extensive
explanationof theconceptsof thistheory.
We will use in the presentation of the approach tothe study ofsymmetry ofconfigurations a
selectedclosurespace<S,f>with thegroup\mathrm{G}=\mathrm{A}\mathrm{u}\mathrm{t}<S,j> of its \mathrm{f}‐automorphisms.Aconfiguration inthisspacewill beanarbitrary,butnotemptyset s\leftarrowof \mathrm{f}‐closed subsets ofS. Itisanatural question
how thecompletelattice ofsubgroupsofthegroup \mathrm{G}is relatedtosymmetriesofconfigurations,i.e.to
symmetriesof subsets ofthecompletelattice\mathrm{L}_{\mathrm{f}}of closedsubsetsin<S,f>.
We will start from a simple observation related to the generalization ofone of examples in BirkhoflPsLatticeTheory [14].Itsproofissoelementarythat it is leftas anexercise.
LEMMA 4.1 Let H beasubsetofagroup Gactingon asetS,such that theidentity$\epsilon$_{G}ofGbelongs
toHDefinethefamily\lrcorner^{\sim_{H}}ofsubsetsofSby VA\subseteq S:A\in J_{H}^{\sim}iff \mathrm{h}\in AV $\varphi$\in H: $\varphi$(x)\in A. Then s_{H}^{\leftarrow}isa
completelattice withrespecttotheorderofinclusionofsets.
Toavoidcomingto toofast conclusionwehavetonotice thatwearenotinterested in stabilizers of setsof elementsof theclosure space<S,f>,Uut of the families of closedsubsets. Thereforewehave
to applythis lemmato the families ofsets of closedsubsets of<S,f>. We will use the notation
introducedin theprevioussectionand theconceptsdefined andexplainedthere.
PROPOSITION 4.2 Let H beasubgroup ofthe groupG=Aut(L).Definethefamilyd_{H}ofsubsets
ofL_{f} by VK\subseteq L_{f}\cdot K\in \mathrm{c}f_{H} iff VA\in KV $\varphi$ eH:$\varphi$^{*}(A)\in K. Thend_{H}isacompletelattice with respecttothe
orderofinclusion ofsets.
PROPOSITION 4.3 Function $\Phi$:H\rightarrow d_{H}definedinProp.4.2 is anti‐isotonefunctionbetweentwo posets, oneofthem (thelatticeofsubgroups ofagroup G)isacompletelattice.
Proof: Let \mathrm{K}beasubgroup ofH.Then \forall \mathrm{K}\subseteq \mathrm{L}_{\mathrm{f}}:\mathrm{K}\in$\theta$_{\mathrm{H}}iff\forall \mathrm{A}\in \mathrm{K}\forall $\varphi$\in \mathrm{H}:$\varphi$^{*}(\mathrm{A})\in \mathrm{K}.But\forall $\varphi$\in \mathrm{K}:
$\varphi$\in \mathrm{H},therefore\mathrm{K}\in$\theta$_{\mathrm{K}}.
Nowwecandefine aGalois connection. ByProposition3.7 and Remark 3.8we know that there
exists a Galois connection betweenthe poset ofcomplete lattices $\theta$_{\mathrm{H}} and the complete lattice of
subgroupsof\mathrm{G}=\mathrm{A}\mathrm{u}\mathrm{t}(\mathrm{j}_{\llcorner \mathrm{f}})\congAut<sp.
PROPOSITION 4.4Thefollowing twofunctionsformaGalois connection:
$\Phi$:H\rightarrow d_{H}defined by VK\subseteq L_{f}K\in d_{H} iff VA\in KV $\varphi$\in H:$\varphi$^{*}(A)\in Kand
$\Psi$: $\theta$\rightarrow Hdefined by \vee $\gamma$ K subgroup of G: $\theta$\displaystyle \subseteq $\epsilon$ f_{K}J=\int $\varphi$\in G: $\varphi$( $\theta$)\subseteq $\theta$ j.The lastequality is a
consequenceofthefactthat\displaystyle \oint $\varphi$\in G: $\varphi$( $\theta$)\subseteq $\theta$ jisasubgroup ofG.
5.
Symmetry
andInformationInorderto combinebothaspectsof information andtoplacethisconceptin thecontextofnon‐
trivial philosophical conceptual framework, the present author introduced his definition of informationintermsoftheone‐manycategorical oppositionwithaverylongandrichphilosophical
wordsasthat, which makesoneoutofmany. Therearetwoways in which manycanUe madeone,
eitherbythe selection ofoneout of many,orby bindingthe manyintoawholebysomestructure. Theformer isaselective manifestationofinformationand the latter isastructural manifestation.They
aredifferent manifestations ofthesame conceptofinformation,notdifferenttypes, asoneisalways
accompanied bytheother,althoughthemultiplicity (many)canbe differentin eachcase.
This dualism between coexisting manifestations was explained by the author in his earlier expositionsofthe definitionusingasimple exampleof thecollectionofthekeystoroomsinahotel. It is easy to agree that theuse ofkeys is based on theirinformational content, but information is
involved in this use in two different ways, through the selection of the rightkey, orthrough the
geometric descriptionof itsshape.Wecanhave numbers oftheroomsattachedtokeyswhich allowa
selection oftheappropriate keyoutofmanyotherplacedonthe shelf.However,wecanalso consider
theshapeofkeysfeathermade ofmechanically distinguishableelementsor evenof molecules. In the
latter case, geometric structure ofthe key is carrying information. The two manifestations of
informationmakeoneoutofverydifferentmultiplicities,buttheyarecloselyinterrelated.
The definition of information presented above, which generalizes many earlier attempts and
which duetoits veryhighlevel of abstractioncanbeappliedtopracticallyall instances of theuseof
theterm information,canbe usedto develop amathematicalformalism for information.Itisnota
surprise,that theformalism isusingverygeneralframework ofalgebra. [16]
Theconceptof informationrequiresavariety (many),whichcanbe understoodas anarbitraryset
\mathrm{S} (called a carrier ofinformation). Information system is this set \mathrm{S} equippedwith the family of subsets s\leftarrow satisfying conditions: entire \mathrm{S} is in s\leftarrow, and together with every subfamily of s\leftarrow, its
intersection belongsto s\leftarrow,i.e. s^{\infty} is aMoore family. Of course, this means that we have a closure
operator\mathrm{f}definedonS.TheMoorefamily s\leftarrowof subsets issimplythefamilyf‐C1 of all closedsubsets, i.e. subsetsA of\mathrm{S} suchthat \mathrm{A}=\mathrm{f}(\mathrm{A}). Thefamily ofciosedsubsets s\leftarrow=\mathrm{f}-\mathrm{C}1 is equipped with the structure of a complete lattice \mathrm{L}_{\mathrm{f}} Uy the set theoretical inclusion. \mathrm{L}_{\mathrm{f}} can play a role of the
generalizationoflogicfornotnecessarily linguisticinformationsystems,althoughit doesnothaveto beaBooleanalgebra. In manycasesit maintainsallfundamental characteristicsofalogical system.
[17]
Information itselfisadistinction ofasubset s_{0}^{\leftarrow}of s^{\infty},such that it is closed withrespectto(pair‐
wise) intersection and is dually‐hereditary, i.e. with each subset belongingto s_{0}^{\leftarrow}, all subsets of \mathrm{S}
includingitbelongtos_{0}^{\leftarrow}(i.e.\triangleleft^{\leftarrow}0 isafilter in \mathrm{L}_{\mathrm{f}}).
The Moore family s\leftarrow canrepresent avariety ofstructures ofaparticulartype (e.g. geometric,
topological, algebraic, logical, etc.) definedon the subsets of S. Thiscorresponds tothe structural manifestation of inforrnation. Filter \mathrm{t}^{\leftarrow}0 in turn, in many mathematical theories associated with localization,canbe usedasatool foridentification, i.e. selectionofanelement within thefamily s\leftrightarrow,
and under some conditions in the set S. For instance, in the context of Shannons selective information based on a probability distribution of the choice ofan element in \mathrm{S}, 30 consists of
elements in \mathrm{S}which haveprobabilitymeasure 1,while\triangleleft^{\leftarrow}issimplythesetofall subsets ofS.
The toolsdevelopedintheprecedingsectionallowustocharacterize s_{0}^{\leftarrow}intermsof itssymmetry. 6. Conclusion
The
approach
presented above can be used forstudy
of symmetry in the context ofarbitrary
closure spaces. Itspresentation
is merelyan outline,which hasto be elaborated in further work. Inparticular,
thematterofspecial
interestis itsapplications
toalready existing
References
[1] Klein,F.C.(1872/2008).AComparativeReviewofRecentResearchesinGeometry (Vergleichende Betrachtungenüberneueregeometrische Forschungen).Haskell,M. W.(Transl.)arXiv:0807.3161v1
[2] Cayley,A.(1854).On thetheory ofgroupsasdependingonthesymbolic equation$\Theta$^{\mathrm{n}}=1.Pkilosophical Magazine,7(42),40‐47.
[3]Jordan,C.(1870).Traitede SubstititionsetdesEquationsAlgebraiques.Paris: Gauther‐Villars.
[4]Noether. E.(1918).InvarianteVariationsprobleme.Nachr. D.König.Gesellsch.D. Wiss.ZuGöttingen, Math-p $\phi$ s.Klasse 1918: 235‐257.
[5]Pasteur,L.(1848).Surles relationsquipeuventexisterentrela formecristalline,lacompositionchimiqueet
lesensdelapolarisationrotatoire(Onthe relations thatcanexist betweencrystallineform,and chemical
composition,and thesenseofrotary polarization),Annales de ChimieetdePhysique,3rdseries,vol.24,no.6,
pages 442‐459.
[6]Bateson,G.(1990).A{\rm Re}‐examination of Batesons Rule.InBateson.G., StepstoanEcology ofMbd
NewYork: BallentineBooks,pp. 379‐396.
[7]Bateson,W.(1894).MaterialsfortheStudy ofVanation.London: Macmillan.
[8]deSaussure,F.(1916/2011).CourseinGeneralLinguistics.Transl. Wade Baskin. New York: Columuia Univ.Press.
[9] Piaget,J.(1968/1972).Le stmcturdism. Paris: Presses Universitaires deFrance;Englff.Stntcluralism.New
York:Harper&Row.
[10]Lévi‐Strauss,C.(1967).StructuralAnthropology.Ttansl.Claire JacoUson and Brooke GrundfestSchoepf. New York:DoubledayAnchor Books.
[11] Weyl,H.(1952). Symmetry.Princeton: Princeton Univ. Press.
[12]Hamermesh,M.(1962). GroupTheoryAndItsApplicationtoPhysicalProblems. Reading,MA:Addison‐
Wesley.
[13] Anderson,P.W.(1972).More is Different.Science, 177(4047),393‐396.
[14] Birkhoff,G.(1967).Latticetheory,3^{rd}.ed American MathematicalSocietyColloquium PuUlications,Vol
XXV, Providence,K I.:American MathematicalSociety.
[15]Schroeder.M. J.(2005). PhilosophicalFoundations for theConceptofInformation: Selective and Structural Information. InProceedings oftheThirdInternationalConferenceontheFoundationsof
InformationScience,Paris2005,\mathrm{h} $\psi$://\mathrm{w}\mathrm{w}\mathrm{w}.mdpi.\mathrm{o}\mathrm{r}y\mathrm{f}\mathrm{i}\mathrm{s}2005/proceedings.\mathrm{h}\mathrm{f}\mathrm{f}\mathrm{n}\mathrm{l}/.
[16] Schroeder,M. J. (2011)FromPhilosophytoTheoryofInformation. International JwmalInformation TheoriesandApplications, 18(1),2011,56‐68.
[17] Schroeder,M. J.(2012.Search forSyllogisticStructure ofSemantic Information. J.Appl.Non‐Classical